The table shows the relationship between the length, in inches, of a rectangular package and the cost to mail it.
Length1 2 3 4
Cost\$3.50 \$8.50 \$23.50 \$54.50
The equation $C(l)=l^3-l^2+l+2.5$ models the cost to mail a package as a function of its length. To the nearest quarter inch, approximately what is the length of a package that costs $\$11.00$ to mail? Enter your answer as a decimal.
Length | 1 | 2 | 3 | 4 |
Cost | \$3.50 | \$8.50 | \$23.50 | \$54.50 |